f40bfc9267
Change-Id: Id7f4717d51ed02d67cb9f9cb3c0ada4a81843f97 Reviewed-on: http://gerrit.rockbox.org/137 Reviewed-by: Nils Wallménius <nils@rockbox.org> Tested-by: Nils Wallménius <nils@rockbox.org>
111 lines
3.8 KiB
C
111 lines
3.8 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2009 Mohamed Tarek
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#include <stdlib.h>
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#include <inttypes.h>
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/* Macros for converting between various fixed-point representations and floating point. */
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#define ONE_16 (1L << 16)
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#define fixtof64(x) (float)((float)(x) / (float)(1 << 16)) //does not work on int64_t!
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#define ftofix32(x) ((int32_t)((x) * (float)(1 << 16) + ((x) < 0 ? -0.5 : 0.5)))
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#define ftofix31(x) ((int32_t)((x) * (float)(1 << 31) + ((x) < 0 ? -0.5 : 0.5)))
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#define fix31tof64(x) (float)((float)(x) / (float)(1 << 31))
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/* Fixed point math routines for use in atrac3.c */
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#if defined(CPU_ARM)
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/* Calculates: result = (X*Y)>>16 */
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#define fixmul16(X,Y) \
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({ \
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int32_t lo; \
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int32_t hi; \
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asm volatile ( \
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"smull %[lo], %[hi], %[x], %[y] \n\t" /* multiply */ \
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"mov %[lo], %[lo], lsr #16 \n\t" /* lo >>= 16 */ \
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"orr %[lo], %[lo], %[hi], lsl #16" /* lo |= (hi << 16) */ \
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: [lo]"=&r"(lo), [hi]"=&r"(hi) \
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: [x]"r"(X), [y]"r"(Y)); \
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lo; \
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})
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/* Calculates: result = (X*Y)>>31 */
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/* Use scratch register r12 */
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#define fixmul31(X,Y) \
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({ \
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int32_t lo; \
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int32_t hi; \
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asm volatile ( \
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"smull %[lo], %[hi], %[x], %[y] \n\t" /* multiply */ \
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"mov %[lo], %[lo], lsr #31 \n\t" /* lo >>= 31 */ \
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"orr %[lo], %[lo], %[hi], lsl #1" /* lo |= (hi << 1) */ \
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: [lo]"=&r"(lo), [hi]"=&r"(hi) \
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: [x]"r"(X), [y]"r"(Y)); \
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lo; \
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})
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#elif defined(CPU_COLDFIRE)
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/* Calculates: result = (X*Y)>>16 */
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#define fixmul16(X,Y) \
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({ \
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int32_t t, x = (X); \
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asm volatile ( \
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"mac.l %[x],%[y],%%acc0\n\t" /* multiply */ \
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"mulu.l %[y],%[x] \n\t" /* get lower half, avoid emac stall */ \
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"movclr.l %%acc0,%[t] \n\t" /* get higher half */ \
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"lsr.l #1,%[t] \n\t" /* hi >>= 1 to compensate emac shift */ \
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"move.w %[t],%[x] \n\t" /* combine halfwords */\
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"swap %[x] \n\t" \
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: [t]"=&d"(t), [x] "+d" (x) \
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: [y] "d" ((Y))); \
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x; \
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})
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#define fixmul31(X,Y) \
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({ \
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int32_t t; \
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asm volatile ( \
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"mac.l %[x], %[y], %%acc0\n\t" /* multiply */ \
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"movclr.l %%acc0, %[t]\n\t" /* get higher half as result */ \
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: [t] "=d" (t) \
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: [x] "r" ((X)), [y] "r" ((Y))); \
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t; \
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})
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#else
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static inline int32_t fixmul16(int32_t x, int32_t y)
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{
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int64_t temp;
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temp = x;
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temp *= y;
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temp >>= 16;
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return (int32_t)temp;
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}
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static inline int32_t fixmul31(int32_t x, int32_t y)
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{
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int64_t temp;
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temp = x;
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temp *= y;
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temp >>= 31; //16+31-16 = 31 bits
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return (int32_t)temp;
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}
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#endif
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